Question

Assertion (A): The valency of aluminium is 3 and oxygen is 2. 1

Reason (R): The chemical formula of aluminium oxide is Al3O​

Answer 1

Valency of an atom is the number of electrons that are required to be added or removed from the outermost shell of an atom to complete its octate.

Alumunium has an atomic number (Z) of 13

So, its electronic configuration is [Ne] 3s² 3p¹

1

Hence, it needs to lose 3 electrons to attain stable configuration, hence its valency is three.

Oxygen has an atomic number (Z) of 18

So, its electronic configuration is [He]2s² 3p¹.

Therefore, it needs to gain more electrons to attain stable ocate. Hence, its valency is 2

Answer 2

Answer:

Valency of an atom is the number of electrons that are required to be added or removed from the outermost shell of an atom to complete its octate.

Alumunium has an atomic number (Z) of 13

So, its electronic configuration is [Ne] 3s² 3p¹ 1

Hence, it needs to lose 3 electrons to attain stable configuration, hence its valency is three.

Oxygen has an atomic number (Z) of 18

So, its electronic configuration is [He]2s² 3p¹.

Therefore, it needs to gain more electrons to attain stable ocate. Hence, its valency is 2

mark as brainly